6. Lung Cancer Flashcards
What are the 3 most common cancers in order?
Breast
Prostate
Lung
What is the biggest cause of lung cancer?
Smoking, 80%
Radon gas exposure also causes a small % of cases
Outline the thoracic anatomy
Trachea
Splits into left and right main bronchi
Bronchi then split into lobar bronchi
Segmental bronchi
Bronchioles
Alveoli
How many lobes does each lung have?
Right - 3 lobes
Left - 2 lobes
Not enough space on left for 3 lobes due to heart
Both have oblique fissure
Right also has horizontal fissure
What is the membrane called that surrounds the lungs?
Visceral pleura
Parietal pleura is the chest wall
Where is the pleural cavity?
Potential space between the visceral and parietal pleura
Negative pressure pulls the pleural layers close together
As the chest expands, negative pressure in the pleural cavity pulls the lungs towards the chest wall causing them to expand
What does a pleural effusion do to the pleural pressures?
Inward pressure on the lungs, reducing lung volume
How is lung cancer broadly divided?
Small cell lung cancer (20%)
Non-small cell lung cancer (80%)
How is non-small cell lung cancer divided?
Adenocarcinoma (40%)
Squamous cell carcinoma (20%)
Large cell carcinoma (10%)
Other types (10%)
What type of lung cancer is most common in non-smokers?
Adenocarcinoma
What type of cancer is most common in smokers?
Squamous cell
Where do squamous cell carcinomas and adenocarcinomas develop in the lung?
Squamous
Develop centrally from epithelial cells lining airways
Take longer to metastasise
Cavitating lesions
Adenocarcinomas
Develop from peripheral mucous secreting cells
Bronchial or alveolar wall
More common in women than men
What are squamous cell cancers more likely to do?
Lobar collapse or infection due to blockage of airways
Where do large cell carcinomas develop?
Throughout the lung
Undifferentiated structure
Centrally or peripherally
Where do Small cell cancers arise from?
APUD cells
Central carcinomas
Fast growing and metastasise early
Why do small cell lung cancers cause paraneoplastic syndromes?
They contain neurosecretory granules which can release neuroendocrine hormones
What are the 5 paraneoplastic syndromes asscoiated with lung cancer?
Small cell
SIADH
- Ectopic ADH secretion so hyponatraemia
Cushing’s Syndrome
- Ectopic ACTH secretion so more glucocorticoids made
Lambert Eaton Syndrome
- Antibodies to voltage gated calcium channels
- Similar to myasthenia gravis
Squamous cell carcinoma
Hypercalcaemia
- Stones, bones, groans
- Due to bony metastases and secretion of PTHrP and calcitriol
Hypertrophic osteoarthropathy
- Clubbing and periostitis
- Symmetrical, painful arthropathy affecting the distal joints
What happens to PTH in hypercalcaemia related to SCC?
Low PTH
Due to negative feedback from hypercalcaemia, raised PTHrP
What are some differential diagnoses for symptoms of lung cancer?
Pneumonia
Pulmonary TB
PE
Heart failure
What is a mesothelioma?
Lung malignancy affecting mesothelial cells of the pleura
Strongly linked to asbestos
Latent period of up to 45 years
Poor prognosis, chemotherapy can improve survival but mainly palliative
How does lung cancer present?
SOB
Cough
Haemoptysis
Finger clubbing
Recurrent pneumonia
Weight loss
Lymphadenopathy- supraclavicular nodes
What causes haemoptysis and coughing in lung cancer?
Unstable tumours cause blood vessels to break and bleed
Tumour irritates airways activating cough reflex
What type of wheeze is heard in lung cancer?
Monophonic wheeze
Tumour causes narrowing of single airway
What extrapulmonary manifestation is indicated by a hoarse voice?
Recurrent laryngeal nerve palsy
Tumour presses on the recurrent laryngeal nerve as it passes through the mediastinum
What causes a phrenic nerve palsy in lung cancer?
Nerve compression by tumour
Causes diaphragm weakness and SOB
What happens in a SVC obstruction?
Direct compression of the tumour on the SVC
Facial swelling
Difficulty breathing
Distended neck veins and upper chest veins
What is Pemberton’s sign?
Raising hands over head causes facial congestion and cyanosis
This is because there is increased obstruction to SVC drainage due to mass pushing against the SVC
What causes Horner’s syndrome?
Pancoast tumour (adenocarcinomas)
Ptosis
Anhidrosis
Miosis
Tumour presses on the sympathetic ganglion
What causes SIADH?
Ectopic ADH secreted by small cell lung cancer
Hyponatraemia
What causes Cushing’s syndrome in lung cancer?
Ectopic ACTH by small cell lung cancer
What causes hypercalcaemia in lung cancer?
Ectopic PTH by squamous cell carcinoma
What is limbic encephalitis?
Paraneoplastic syndrome
Small cell lung cancer causes immune system to make antibodies which attack the limbic system in the brain
Leads to :
- Short term memory loss
- Hallucinations
- Confusion
- Seizures
anti-Hu antibodies
What happens in Lambert-Eaton myasthenic syndrome?
Antibodies produced by immune system against small cell lung cancer
Antibodies also target and damage voltage-gated calcium channels on presynaptic terminals in motor neurones
Weakness in proximal muscles, intraocular muscles and pharyngeal muscles
- Diplopia
- Ptosis
- Slurred speech
- Dysphagia
- Proximal muscle weakness
Other symptoms
- Dry mouth
- Blurred vision
- Impotence
- Dizziness
What is the referral criteria for lung cancer?
CXR within 2 weeks to patients over 40 with :
- Clubbing
- Lymphadenopathy (supraclavicular)
- Recurrent or persistent chest infections
- Thrombocytosis
- Chest signs of lung cancer
When should patients also be given a CXR?
Over 40 with :
- Two or more unexplained symptoms that have never smoked
- One or more unexplained symptoms that have smoked
What are unexplained symptoms in relation to lung cancer?
Cough
SOB
Fatigue
Chest pain
Weight loss
Loss of appetite
What is the first line investigation in suspected lung cancer?
Chest x-ray
Hilar enlargement
Peripheral opacity (visible lesion in lung field)
Pleural effusion (unilateral usually)
Diaphragm collapse or lung collapse
FBC and CRP - exclude infectious causes
U&Es and bone profile
How does lobar collapse present on CXR?
- Tracheal deviation towards side of collapse
- Mediastinal shift towards side of collapse
- Elevation of the hemidiaphragm
What other investigations can be used in confirmed lung cancer?
CT CAP with contrast
- Assess TNM status
- Using contrast gives more information about different tissues
PET-CT
- Radioactive tracer, images taken with a CT scanner and gamma-ray detector
- Useful to see if cancer has spread by showing increased metabolic activity
Bronchoscopy with endobronchial USS (EBUS)
- Endoscopy with USS on scope
- Allows details tumour assessment and USS guided biopsy
Histological diagnosis
- Biopsy to check type of cells in tumour
- By bronchoscopy or percutaneous biopsy
How is lung cancer treated?
MDT meeting
Surgery
First-line in non-small cell lung cancer
Disease isolated in single area
Entire tumour removed
Radiotherapy
Can be curative in non-small cell lung cancer when diagnosed early
Chemotherapy
Can be offered in addition to surgery or radiotherapy in certain patients to improve outcomes
Or palliative to imrpove survival and QoL in later stages of non-small cell lung cancer
Endobronchial stenting or debulking
Can be used as part of palliative to relieve bronchial obstruction from lung cancer
How is small cell lung cancer treated?
Chemotherapy and radiotherapy
Prognosis is worse than non-small cell
What gene mutations present in lung cancer are favourable for treatment?
EGFR-TK
ALK
ROS-1
On T-Cells
PD-L1 at 50% or above if no above mutations
What is Systemic anti-cancer therapy (SACT) used in non-squamous NSCLC?
If these mutations are present checkpoint inhibitors are used
Epidermal growth factor receptor tyrosine kinase (EGFR-TK) mutation:
Afatinib, erlotinib and gefitinib
Anaplastic lymphoma kinase-positive (ALK) gene rearrangement:
Crizotinib, ceritinib and alectinibs
If NSCLC has no gene mutations so cannot have systemic anti cancer therapy, what chemotherapy are they offered instead?
Usually platinum based
What is the prognosis in lung cancer?
One year survival - 40%
Five year survival - 15%
What is the prognosis of small cell lung cancer?
1-3 months if untreated
15 months with chemotherapy
What is done prophylactically in SCLC?
Prophylactic cranial radiotherapy as 50% develop brain mets
How is small cell lung cancer staged?
VALSG staging
Limited disease: tumour not spread beyond hemithorax, regional nodes that may be treated with single radiotherapy field
Extensive disease: tumour spread beyond hemithorax or extensively through the hemithorax, distant metastasis, malignant effusions or contralateral hilar/supraclavicular involvement
TNM used for NSCLC
When is lung cancer surgery contraindicated?
Stage IIIb or IV
FEV < 1.5
Malignant pleural effusion
Tumour near hilum
SVCO
What options are there for removing a lung tumour?
Segmentectomy or wedge resection
Lobectomy
Entire lobe containing tumour removed (most common)
Pneumonectomy
Removing entire lung
Sleeve resection
Removing one lobe and part of the bronchi
What are the different types of surgery for lung cancer?
Thoracotomy
Open surgery, incision and separation of rib to access thoracic cavity
Video-assisted thorascopic surgery (VATS)
Keyhole surgery
Robotic surgery
What type of surgery is preferred in lung cancer?
Minimally invasive e.g. VATS or robotic
Faster recovery and fewer complications
What are the main thoracotomy incisions?
Anterolateral thoractomy
Incision around front and side
Axillary thoracotomy
Posterolateral thoracotomy
Incision around back and side (most common)
What is the done differently between thorascopic surgery and laparosopic?
Thorascopic is done by deflating the lung
Laparoscopic the abdomen is inflated
What indicates a pneumonectomy vs lobectomy on examination?
If there is a thoracotomy scar and there is no breath sound on that side
Indicates entire lung removal rather than lobectomy
If absent lung sounds in a specific area, indicates a lobectomy
Why is a chest drain left in after thoracic surgery?
Allows air and fluid to leave the thoracic cavity and lungs to expand
Chest drain pump can be used to suck fluid and air out of chest
How does a chest drain work?
External end placed underwater
Creates a seal to prevent air going back through drain into chest
Air can still exit chest and bubble through water, but water prevents air re-entering
Water in drain will rise and fall due to changes in chest pressure - swinging
What are the symptoms of pneumonitis?
- Shortness of breath
- Low sats
- Fever
- Cough
- Chest pain with breathing
Do CXR, Chest CT, Lung function tests and bloods/sputum to rule out infection
How is radiation pneumonitis treated?
Prednisolone long-term
Oxygen therapy
NSAIDs
Bronchodilators
Treat the same as pulmonary fibrosis
Before thoracic surgery what should be done in all patients?
Peak flow and spirometry
Calculate predicted post-operative respiratory capacity to guide the type or resection
Pneumonectomy - 50% reduction in FEV1
Lobectomy - 20% reduction
Therefore >1L in lobectomy
>2L in pneumonectomy
